It would be A keeping lakes and rivers free of pollution im pretty sure im on the question myself but im pretty sure that i got it right.
Answer:
The first step of investigation is to verify the existence of the infectious disease outbreak
Explanation:
Plants are in the ground with soil
It is called ELECTRODE.
When performing electrotherapy procedure, the electrode, which is an apparatus of current conductor is used to direct the current from the appliance to the patient's skin.
Electrotherapy procedure involves the use of electrical energy for medical treatment.